(1) Field of the Invention
The present invention relates to a patterning method for micro-contact printing which makes it possible to form micro-contact printed patterns with a size as large as a molecule used in the production of a variety of functional molecular devices and a DNA chip and printed product obtained by this method.
(2) Description of the Prior Art
In the field of molecular chemistry, L. Carter proposed the concept of a molecular device in 1982. Research and development in this field has been actively carried out in enterprise, university and research institutes since that time. For example, if a specific function is given to each organic molecule, respectively and an assembly of these organic molecules is formed, the assembly of organic molecules makes possible the formation of a semiconductor device with a super-high integrated density such that there is no comparison between the integrated density of a semiconductor device formed of the assembly of organic molecules and that of a conventional semiconductor device. Further, in recent years, the genome analysis of DNA has been actively studied and the so-called biochip has attracted the attention of people. The application thereof is also thought for the development of the biochip.
On the other hand, in photolithography employed until now as a method of reproducing micro-contact printed patterns, there is a limit for the reproduction of micro-contact printed patterns in respect of mass-production of micro-contact printed patterns being made in a short time since a substrate with desired micro-contact printed patterns should be reproduced through several steps. Further, photolithography is not suited for materials with a low heat resistance and low mechanical resistance such as cells, DNA and enzymes, since photolithography is carried out through complicated steps such as exposure, development and etching. Further, printing method makes possible the production of massive printed products. However, the reproduction of micro-contact printed patterns of the order of hundreds xcexcm is the limit until now. Accordingly, a printing method is not suited for the reproduction of micro-contact printed patterns.
Inventors of the present invention previously invented a method of reproducing micro-contact printed patterns comprising the steps of: forming patterns of molecules with a polarity on a substrate using molecular ink including molecules with a fixed polarity dispersed in a solvent to form a first transfer layer and forming patterns of molecules with the same polarity as the above-mentioned polarity or a different polarity from the above-mentioned polarity on the substrate using molecular ink including molecules with the same polarity as the above-mentioned polarity or the different polarity from the above-mentioned polarity (Japanese patent application No. 2000-151157).
However, in the above-mentioned method, the density of the ink used is lowered for increasing the resolving power. The film of the first transfer layer has defects since the first transfer layer is transferred using an ink with a thin density. When the second transfer layer is formed, the ink for the second transfer layer comes in and contaminates the first transfer layer formed previously because an area of the first transfer layer is not covered completely with ink for the first transfer layer, so that the contrast between the first transfer layer and the second transfer layer is lowered.
Further, there is a problem that if the density of the ink for the first transfer layer is increased in order to remove defects of the first transfer layer in forming the first transfer layer, the running and spreading of ink occurs so that the resolving power is lowered.
It is an object of the present invention to provide a patterning method for micro-contact printing which makes it possible to form briefly micro-contact printed patterns of a molecular level with a contrast between a printed area and an unprinted area around the printed area, and its printed product.
The present invention, which solves the problem concerning a patterning method for micro-contact printing, is characterized by a patterning method for micro-contact printing comprising the steps of: applying a resin on a master having projected patterns, hardening the resin; removing the hardened resin from the master to make a stamp of the resin; applying a molecular ink including hydrophobic molecules dispersed in a solvent on the stamp; forming micro-contact printed patterns of a hydrophobic molecular layer on a substrate by means of the stamp on which the molecular ink is applied; and dipping the substrate with micro-contact printed patterns in a hydrophilic molecule solution dispersed in a solvent to give chemical modification to the areas of the surface of the substrate around the micro-contact printed patterns, wherein a solution including hydrophilic molecules having a chain length shorter than the chain length of the hydrophobic molecules included in the molecular ink is used as the hydrophilic molecule solution.
According to the present invention, micro-contact printed patterns formed of a hydrophobic molecular layer are formed on a substrate using a hydrophobic molecular ink including hydrophobic molecules dispersed in a solvent and the so-called micro-contact printed patterns are formed of hydrophobic molecules having a chain length longer than the chain length of the hydrophilic molecules. Accordingly, in case that hydrophobic molecular layer has defects, when dipping an area of the substrate uncovered with the hydrophobic molecular layer, namely, an unprinted area into a hydrophilic solution, the hydrophilic solution comes in the defects. However, even in this case, since the hydrophilic molecules coming in the defects are covered with the hydrophobic molecules having a chain length longer than that of the hydrophilic molecules, the high contrast between micro-contact printed patterns and unprinted area of hydrophilic molecules can be obtained without the hydrophobic property of the micro-contact printed patterns being damaged.
An embodiment of the present invention, which solves the problem concerning a printed product, is characterized by a printed product provided with micro-contact printed patterns of a hydrophobic molecule layer formed on a substrate using a molecular ink including hydrophobic molecules dispersed in a solvent and with a hydrophilic molecule layer formed on areas of the surface of the substrate around the micro-contact printed patterns, wherein the chain length of hydrophilic molecules is shorter than the chain length of hydrophobic molecules.
Another embodiment of the present invention, which solves the problem concerning a patterning method for micro-contact printing, is characterized by a patterning method for micro-contact printing comprising the steps of: applying a resin on a master having projected patterns, hardening the resin and thereafter removing the hardened resin from the master to make a stamp of the resin; applying a molecular ink including hydrophilic molecules dispersed in a solvent on the stamp; forming micro-contact printed patterns of hydrophilic molecular layer on a substrate by means of the stamp on which the molecular ink is applied; and dipping the substrate with micro-contact printed patterns in a hydrophobic molecule solution including hydrophobic molecules dispersed in a solvent to give chemical modification to areas of the surface of the substrate around the micro-contact printed patterns, wherein a solution including hydrophobic molecules having a chain length shorter than the chain length of hydrophilic molecules included in the molecular ink is used as the hydrophobic molecule solution.
According to the inventive patterning method for micro-contact printing, a hydrophobic molecular layer is formed on an area of a substrate around micro-contact printed patterns of a hydrophilic molecular layer formed on a substrate using hydrophilic molecular ink including hydrophilic molecules dispersed in a solvent. Accordingly, in case the hydrophobic molecular layer has defects, when dipping an area of the substrate uncovered with the hydrophilic molecular layer, namely an unprinted area into hydrophobic solution, the hydrophobic solution comes in the defects. However, even in this case, since the hydrophobic molecules coming in the defects are covered with the hydrophilic molecules having a chain length longer than that of the hydrophobic molecules, the high contrast between micro-contact printed patterns and unprinted area of hydrophobic molecules can be obtained without the hydrophilic property of micro-contact printed patterns being damaged.
The present invention, which solves the problem concerning a printed product, is characterized by a printed product with micro-contact printed patterns of a hydrophilic molecule layer formed on a substrate using a molecular ink including hydrophilic molecules dispersed in a solvent and with a hydrophobic molecule layer formed on areas of the surface of the substrate around the micro-contact printed patterns, wherein the chain length of hydrophobic molecules is shorter than the chain length of hydrophilic molecules.
The present invention is also characterized by a patterning method for micro-contact printing comprising the steps of: applying a resin on a master having projected patterns, hardening the resin and thereafter removing the hardened resin from the master to make a stamp of the resin; applying a molecular ink including hydrophobic molecules dispersed in a solvent on the stamp; forming micro-patterns of a hydrophobic molecular layer on a substrate by means of the stamp on which the molecular ink is applied; and dipping the substrate with micro-contact printed patterns in a hydrophilic molecule solution including hydrophilic molecules dispersed in a solvent to give chemical modification to areas of the surface of the substrate around the micro-contact printed patterns, wherein after forming the micro-contact printed patterns, chemical modification is given to the areas of the surface of the substrate around the micro-contact printed patterns by the hydrophilic molecular ink in the water.
According to the inventive patterning method for micro-contact printing, after forming the micro-contact printed patterns of a hydrophobic molecular layer on a substrate using a molecular ink including hydrophobic molecules dispersed in a solvent, chemical modification is given to the areas of the surface of the substrate around the micro-contact printed patterns by the hydrophilic molecular ink in the water under such a state that the hydrophobic molecules are bonded with each other with hydrophobic bonds in the water, so that the probability that hydrophilic molecules come in the hydrophobic molecular layer is low. Accordingly, the high contrast between micro-contact printed patterns and an area of the substrate around the micro-contact printed patterns to which the chemical modification is given with the hydrophilic molecular ink can be obtained without the hydrophobic property of the micro-contact printed patterns being damaged.
The present invention, which solves the problem concerning a patterning method for micro-contact printing, is characterized by a patterning method for micro-contact printing comprising the steps of: applying a resin on a master having projected patterns, hardening the resin; removing the hardened resin from the master to make a stamp of the resin; applying a molecular ink including hydrophilic molecules dispersed in a solvent on the stamp; forming micro-contact printed patterns formed of a hydrophilic molecular layer on a substrate by means of the stamp on which the hydrophilic molecular ink is applied; and dipping the substrate with micro-contact printed patterns in a hydrophilic molecule solution including hydrophilic molecules dispersed in a solvent to give chemical modification to areas of the surface of the substrate around the micro-contact printed patterns, wherein after forming the micro-contact printed patterns, chemical modification is given to the areas of the surface of the substrate around the micro-contact printed patterns by the hydrophobic molecular ink in an organic solution.
According to the inventive patterning method for micro-contact printing, after forming the micro-contact printed patterns of a hydrophilic molecular layer on a substrate using a molecular ink including hydrophilic molecules dispersed in a solvent, a hydrophobic molecular ink is applied on the areas of the surface of the substrate around the micro-contact printed patterns in an organic solution, so that the probability that hydrophilic molecules come in the hydrophobic molecular layer is low. Accordingly, the high contrast between micro-contact printed patterns and an area of the substrate around the micro-contact printed patterns can be obtained without the hydrophobic property of micro-contact printed patterns being damaged.
An embodiment of the present invention, which solves the problem concerning a printed product, is characterized by a printed product provided with micro-contact printed patterns of a hydrophobic molecular layer formed on a substrate using a hydrophobic molecular ink including hydrophobic molecules and a hydrophilic molecular layer formed on areas of the surface of the substrate around the micro-contact printed patterns, wherein the printed product is produced utilizing the properties of the hydrophobic molecules of the micro-contact printed patterns being cohesive by cohesive connection in the water.
An embodiment of the present invention, which solves the problem concerning a printed product, is characterized by a printed product provided with micro-contact printed patterns of a hydrophilic molecular layer formed on a substrate using a hydrophilic molecular ink including hydrophilic molecules and a hydrophilic molecular layer formed on areas of the surface of substrate around the micro-contact printed patterns, wherein the printed product is produced utilizing the properties of hydrophilic molecules of the micro-contact printed patterns being cohesive by hydrogen connection in the organic solution.